The LTE (Long Term Evolution) system, which is the 3.9th generation wireless communication system for a mobile phone, employs HARQ (Hybrid Automatic Repeat Request) which is a retransmission control method of performing error detection of a transmission packet between a base station and a mobile station and transmitting a packet having caused an error again. This retransmission control checks a packet error by using CRC (Cyclic Redundancy Check) added to the transmission packet and transmits NACK (Negative Acknowledgement) which is a retransmission request signal when the received packet has not been able to be decoded correctly. Furthermore, ACK (Acknowledgement) which is a transmission acknowledgement signal is transmitted when the transmitted packet has been received correctly (refer to Non-patent document 1).
The retransmission control includes Non-adaptive ARQ and Adaptive ARQ. While Non-adaptive ARQ transmits data in retransmission by the same transmission method as that at the time of initial transmission, Adaptive ARQ transmits retransmission data different from that in the initial transmission by changing a parameter such as a modulation scheme, a coding rate, a puncture pattern, a frequency band width to be used, transmission power (refer to Patent document 1). Furthermore, there is proposed a method of using a plurality of antennas at the time of the retransmission, such as STTD (Space Time Transmit Diversity) and MIMO (Multiple-Input Multiple-Output) which are transmission diversity methods (refer to Patent document 2).